This application claims the priority of German Patent Document 199 43 001.2, filed Sep. 9, 1999, the disclosures of which is expressly incorporated by reference herein.
The invention relates to a cylinder head for a water-cooled internal combustion engine which in use has at least one hot site caused by radiant heat of a combustion space at a wall of the cylinder head, which hot site is cooled by a cooling duct through which cooling water is flowing.
A cylinder head for a valve-controlled internal combustion engine with water cooling is known from European Patent Document EP 0088 157 A 1 and comprises cylinder head measures for decreasing thermal loads. For this purpose, a nozzle-like main water crossing is provided, which produces a flow acting between exhaust and refill ducts.
In FIG. 3, European Patent Document EP 0353988 A1 shows a cylinder head, which is water cooled and has a hot site in the region of one wall of the cylinder head. The hot site extends between a central spark plug and a combustion space.
U.S. Pat. No. 2,305,457 deals with a water-cooled cylinder head with cooling ducts extending around exhaust valves. These cooling ducts, in the vicinity of the exhaust valves, have walls which are cooled by means of a cooling medium distributed over spray nozzles.
Finally, German Patent Document DE 3412 052 C2 is concerned with a cylinder head which is provided with valves that are surrounded by valve-seat rings. These valve-seat rings are bounded by annular ducts which carry the cooling water.
It is an object of the invention to configure a cooling duct of a cylinder head of an internal combustion engine in such a manner that, in particular, pronounced hot sites of the cylinder head are cooled with flowing cooling water.
Pursuant to the invention, this objective is accomplished by providing a cylinder head for a water-cooled internal combustion engine which in use has at least one hot site brought about by radiant heat of a combustion space at a wall of the cylinder head, which hot site is cooled by means of a cooling duct through which cooling water is flowing, wherein flow structure carrying additional cooling water is provided in the cooling duct for a concerted flow of cooling water and for cooling the hot site at the wall of the cylinder head.
The following description and the claims describe advantageous features of preferred embodiments of the invention.
Advantages achieved with the invention are that the flow measures carrying additional cooling water bring about a concerted flow of cooling water and cooling in the region of the hot site, that is, at the wall of the cooling duct, which extends, for example, between the central spark plug and a combustion space. The flow measures are particularly effective if they are formed by one or more additional ducts, at least one additional duct being directed onto the hot site. This additional duct is connected with a duct supplying cooling water which is provided in a cylinder housing mounted at the cylinder head. Moreover, in addition to the flow measures, one or more control measures are disposed in the cooling duct and likewise ensure a concerted flow of cooling water and cooling of the hot site at the wall of the cylinder head. The flow measures and the control measures bring about a concerted flow of the cooling water to the hot site and thus reduce the risk of a temperature-induced excessive stress. In turn, this makes it possible, on the one hand, to use standard materials (AlSi 10 and AlSi 7) for the structural design of the cylinder head and, on the other, to reduce clearly the number of defective units, which are particularly costly especially in the case of cylinder heads of internal combustion engines.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.